Inspection for microcracking in sealants, coatings, and composites is labor-intensive, and adequate detection is not always possible with the current inspection methods. In order for automated microcracking detection processes to offer an advantage over current methods, the precision of automated processes must be improved and ensured.
Present systems for detection of microcracking are typically contact (i.e. not remote) in nature, and are limited in speed, environment, and automation capability. Imaging systems that operate in the visible spectrum suffer from spectral interference, thereby making it difficult to discern the cracks in the material. X-ray inspection can image beneath a material surface, but the associated safety concerns with X-ray use makes their application prohibitive in a large-scale manufacturing environment. THz systems can image underneath surfaces, but poor spectral discrimination makes it difficult to obtain an adequate signal to noise ratio. A single THz imaging device can be used to generate a flat image of a surface, but this flat image does not yield information about crack depth in surface films or crack geometry in sub-surface films.
As such, there is a need for an improved microcracking detection solution.